One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,3)(4,6,8,7)(9,10)(11,15)(12,13)(14,16)(18,20)(22,23)(25,26,29,30)(27,33,35,31)(28,32,36,38)(34,40,37,39)(4,8)(6,7)(9,11,14,12)(10,15,16,13)(18,20)(22,23)(26,30)(28,36)(31,33)(34,37)(2,3)(6,7)(10,16)(11,12)(17,18,21,20)(19,23,24,22)(25,26)(27,31)(28,32)(29,30)(33,35)(34,39)(36,38)(37,40)(1,3,5,2)(4,7,8,6)(9,12,14,11)(10,15,16,13)(17,19,21,24)(18,22,20,23)(25,27)(26,31)(28,37)(29,35)(30,33)(32,40)(34,36)(38,39)(1,4,5,8)(2,6,3,7)(9,13,14,15)(10,11,16,12)(17,20,21,18)(19,23,24,22)(25,28)(26,32)(27,34)(29,36)(30,38)(31,39)(33,40)(35,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.